Figure on at least 4 hours minimum. Some Task Forces can be done in less, especially if there are members who have done the TF before. The TF members can log ogg and log back on without stopping the TF unless enough members quit the TF to take the team down under a certain minimum number (varies by TF). Currently one of my alts is in the middle of the Positron Task Force, but the team only plays a couple of hours at a time on weekends, so while it willl only take us about five hours of actually play those hours have been stretched out over four weeks now.
